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Sewer Lateral Inspection & Repair

Approved at a public hearing during the Board of Directors meeting held May 9, 2018, and further authorized through Resolution 2018-07, the following is in effect:

All sewer lateral repairs and new sewer lateral construction in the Tam Valley area require a permit issued from Tamalpais Community Services District (TCSD).

A Lateral Permit ensures that repairs and construction projects in the public right-of-way will be performed to meet standards set by TCSD and the County of Marin, and insures the safety of the public during the process.

When do I need a permit?

A Lateral Permit is required any time someone encroaches in the public right-of-way, replaces or makes repairs to the sewer lateral, either for construction work on private property, sidewalks, driveway approaches, or underground utilities.

Apply for a lateral permit

Lateral permit applications may be obtained from our district office located at 305 Bell Lane, Mill Valley CA, 94941, or you can download the application here:


Please refer to the adopted Fee Schedule below for permits issued by TCSD. If a Lateral Permit needed does not fit in a category below, the permit fee is based on Capacity Charge (new construction) & Connection Fee/Inspections. A security bond may also be required for construction, sewer/lateral and sidewalk projects.

Capacity Charge

Single Family Residential $17,384 - Per DU

Duplexes $11,591  - Per DU

Multi-Family $9,933 - Per DU

Commercial $17,384 - Per EDU

(DU = dwelling unit EDU = equivalent dwelling unit)

Connection Fee/Inspections

Single Family Residential $571

Multi-Family Residential Actual time & material costs
(minimum charge $571)

What do I do once I obtain a permit?
Once a Lateral Permit has been issued, work or placement of dumpsters or other approved items may begin. Any conditions and inspections noted on the permit must be complied with and followed. Interim and final inspections are required for all construction projects. In most cases, Lateral Permits are valid for a period of 30 days from date approved, but may be extended upon review and approval with payment of additional fees.

Installation Requirements for 4" Laterals

The following are requirements provided by the District's Ordinance 96 in the Tamalpais Community Services District and must be adhered to in the construction of sewer laterals in this district.


1. A permit must be obtained at the office of the Tamalpais Community Services District.

2. All permit, inspection and connection fees must be paid before connection to the district sewer system.


All work shall be subject to at least two inspections by district staff. One inspection to be performed before the sewer lateral is covered and one after covering the sewer lateral, placing clean-outs and installation of back flow prevention devices. (Additional return visits/re-inspections are subject to additional charges)

1. For single residences, multiple units and commercial buildings up to 150 drainage fixture units, where the lateral has a fall of at least one fourth (1/4) inch per foot (2 percent slope), a 4 inch sewer lateral is acceptable.
2. For all others a 6 inch line is required.

Cast iron, HDPE, C900, SDR 26 which is FHA approved, with solvent weld or rubber ring joints is required. Couplings are to be shear banded type & properly torqued. ABS and clay pipe are not acceptable.

One fourth (1/4) inch per foot or 2 percent, except one-eighth (1/8) inch per foot will be allowed in unusual circumstances and six (6) inch pipe shall be used for all multiple dwellings. The contractor shall provide a builder’s level to allow the inspector to check the grade.

Cover above the pipe shall be 36 inches in public driveways and streets or unpaved driveways, 24 inches in private driveways and 18 inches in all other areas, except in extenuating circumstances. Deviations will be allowed providing the pipe is fully encased in concrete and has been approved by district inspector.

  1. Backfill shall consist of URB or quarry fines only, compacted and jetted for settlement (3/4 crushed rock). The pipe shall be firmly bedded in the trench bottom along its entire length and the backfill will be free from stones or rock greater than 1 inch and shall be hand tamped to the top of the pipe. In county maintained roads, bedding and backfill shall confirm to county or state requirements.
  2. No line shall be backfilled or covered prior to testing and inspection by district staff.
  1.  All public streets and driveways shall be restored to County or State requirements.
  2. All necessary encroachment permits shall be obtained by the contractor from the governing authority.
  1. Connection to the district’s public sewer shall be made at a downstream angle of 45 degrees. The flow line of the lateral shall be above the spring line of the main and shall drop down to enter the main in accordance with the district’s standard detail, as instructed.
  2.  Connection shall be made using an approved wye fitting & couplings where lateral stub is not provided.
  3.  When connecting into a manhole, the connection shall be made at flow line of the main. If this is not possible, the connection shall intersect the manhole no more than a few inches above the bench.
  1. A clean-out (TEE) shall be provided within 24 inches of a building, or as close as reasonably possible.
  2. Clean-outs shall be installed at abrupt turns of 90 degrees or higher except where a long radius sweep is used, and in excessively long installations (every 90 feet).
  3. An approved backflow protection device shall be installed at cleanout nearest to the building. The device shall contain an airtight seal at its upper end and shall be a sewer relief device (i.e., sewer popper), or approved equal.
  4. All clean-outs shall be brought to the surface. Christy Box with a metal lid shall be installed if necessary to protect from damage or trip hazard.

All sewers prior to being backfilled shall be subjected to a water test or air test in the presence of the District inspector. Air test is to be no less than 5 pounds for 3 minutes, water test will be a minimum of 5 minutes.

All sewer lines shall be a minimum of one foot from all other utilities. Sewer lines shall always be laid below any water supply lines.

No sewer shall be put into service until all fees have been paid and the line has been approved by the District. A charge will be levied for disconnecting any illegally connected lateral, pursuant to the provisions of Ordinance 96 and reconnecting will be at the owner’s expense.

Please direct questions to Mike Quecke at 415.388.6393. ex.104

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